Posts Tagged ‘passivhaus’

form factor and passivhaus

September 23, 2014

HH front render

It is well known that compactness is an important aspect of a well designed and cost effective Passivhaus as it has a considerable impact on the overall heat demand.  Having now modeled a number of projects in PHPP (Passive House Planning Package), I decided to do a quick comparison of the ratio of envelope to floor area (known as the form factor) as well as the average R-value of the entire envelope.  Here are a few examples:

Emerson

envelope to treated floor area:  3.8

average R-value:  39.4

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Skidmore

envelope to treated floor area:  3.7

average R-value:  29.7

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18th Ave Residence

envelope to treated floor area: 3.2

average R-value:  24.1

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Haig Haus

envelope to treated floor area:  2.7

average R-value:  25.9

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Ankeny Apts

envelope to treated floor area:  1.5

average R-value:  19.7

 

While there are many variables at play that make each project distinct, it is clear that form factor has a huge impact.  Remember boxy can be beautiful!

 

 

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help wanted

April 27, 2014

In Situ Architecture is looking for some part-time contract help. Excellent rendering and graphics skills a must.  Interest in low energy building and passivhaus is helpful.  If you are interested please email a brief description of yourself with a few examples of your best work.

Info at insituarchitecture dot net

thermos

January 2, 2014

SPH PM

we’re excited to share that skidmore passivhaus is featured in the january 2014 issue of portland monthly magazine!

pick it up at your nearest newsstand.

you can also see an excerpt here:

An Eco-Chic Passive House

if you want more info visit us at:

www.insituarchitecture.net

fast forward

May 20, 2013

we’ve been too busy to post for quite awhile, but work has been progressing nicely on the skidmore house.  here’s a quick look around:

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we hope to be putting the final touches on in the next few weeks.  lots of catching up to do.  check back soon for more on this project and others.

www.insituarchitecture.net

stained cedar siding

February 10, 2013

siding work has mostly wrapped up.  the vertical siding is installed on rainscreen over rigid exterior insulation.  see this past post for more info on the assembly.

here’s a first look at the siding pretty much completed.

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the siding is off the shelf 1×6 channel made from tight knot cedar.  it’s stained with 1 coat of olympic semi-transparent stain in ebony.

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the large south windows (and doors) have exterior motorized aluminum sun shades supplied by hella.  the siding has been detailed to allow the shades to stack in recessed pockets.  in this photo the shades are down about 9 inches and just visible on the 2 living room units (lift / slide door and fixed upper unit).  more on the shading later.

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the “breezeway” features a south facing door / window with a wood canopy (to be painted black) topped with clear tempered glass.

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the entry door at left features acid etched glass for privacy and has a smooth accent panel adjacent that will be painted a deep red.  the wood canopy will painted black and features a simple galvanized metal pan roof.  steel rod will be used to hang the canopy from a bracket mounted to the wall above.  a mahogany deck will eventually complete the front porch.

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the north street facade also features a narrow smooth accent panel that will be painted with the same deep red.  the same siding runs horizontally to form an accent between floors.

check back soon for more.

www.insituarchitecture.net

pre-certified

January 15, 2013

after 6 months of hard work, persistence and a bit of cash, skidmore passivhaus is officially pre-certified.

PHIUS+ pre-cert letter

(next time i will do a more accurate solar shading report BEFORE the start of construction)

solar pathfinder

here are the latest results of the PHPP model:

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more photos soon.

thermal bridge free exterior

December 31, 2012

next up on skidmore passivhaus is installing the outsulation on the walls along with the rainscreen furring.

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the plywood sheathing was first covered by a weather resistive barrier with metal head flashings at the windows and doors.

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most walls get a layer of 3″ poly-iso, while the south wall will get 4″ to match the recessed pocket for the exterior shades.

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2 screws (with plastic washer) per 4×8 sheet hold it in place until the furring strips are installed.

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all seams and fasteners are taped.  the face of the insulation is treated as a second weather resistive barrier.

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additional flashings at all doors and windows will be taped to the insulation as the wood trim is installed.

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1/2″ x 2″ pt plywood furring strips run vertically to create the drainage plane.  they are held in place by just a few fasteners until the next layer is installed.

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since we are using vertical siding, a second layer of furring runs horizontally.  we used pt 1×4 as a solid nailing base for the siding.

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long fasteners secure the second layer of furring strips running horizontally through the foam to the studs.  the straightforward framing layout makes the studs much easier to locate.

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keep in mind that long fasteners get expensive.  we settled on grabber #10 x 6″ square drive coated screws (from nw staple).

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next up on the exterior is trimming windows and installing siding.

stop by again soon.

foundation foam

December 30, 2012

while there’s a lot of talk these days about building without foam, we decided early on to use continuous rigid board foam outsulation for this project.  to begin the foundation gets 4″ of expanded polystyrene.

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these 8′ long pieces are held in place at the bottom by backfill and at the top by concrete spikes.  spray foam was first applied to the back of the pieces to fill gaps and help secure them.

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the concrete spikes are recessed into the foam to minimize thermal bridging.  only 3 spikes were used per 8′ long piece.

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step 1: use hole saw bit and pry out hunk of foam.

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step 2: use hammer drill to drill hole in foundation.

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step 3: prepare 6″ concrete spike and plastic washer.  (concrete spike from dealers supply / plastic washer from service partners supply)

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step 4: hammer spike and washer to secure foam.

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step 5: spray foam any gaps

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step 6: reinstall foam plug using spray foam as adhesive

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when the weather warms we will be applying a cementitious coating direct to the foam to provide the finished surface.  after final grading, only 6″ or so will be exposed to view.

waiting for guffman (or looking through windows – part 8)

December 2, 2012

when we began this process, we only had a few rules.  one of them was real wood high performance windows.

at the conception of this project, we were thinking about making a pretty good house.  Super insulated, airtight, with triple glazed windows and a heat recovery ventilator, but not necessarily passivhaus.  since we ruled out plastic or fiberglass, US built windows were at the top of the list.  once we decided to build to passivhaus, it quickly became clear that we had to look overseas.

our initial pricing was from optiwin, internorn, and pazen.  optiwin was very appealing aesthetically but super expensive.  internorn provided fantastic pricing, but there was no rep in the US meaning distant communications and pretty much zero support. pazen offers a slightly different product with a fiberglass exterior cladding and more minimal frame profiles, but they only offered a stainless steel clad door.  because we had lots of doors, the price jump was huge and they were way out of our budget.

about the same time, our local loewen rep started offering unilux.  we visited another local passivhaus project to see them installed, and we were impressed.  the pricing was strong, and we felt most comfortable having a rep locally, although they only had a limited understanding of passivhaus.  we thought we’d made up our mind, until we stumbled onto zola windows.  nearly identical to the german and austrian made passivhaus windows, zola windows are manufactured in poland and offered at a much more competitive price point.  we worked through all the options, input the data into PHPP, and scrutinized the sample window section that we got our hands on.  it seemed like a good balance between quality, aesthetics, and price point.  decision made.

one of the biggest challenges of using european windows is the long lead time (for our order the lead time was estimated at 12-16 weeks).  we worked hard to have our window order ready to go by the time we were breaking ground.  once we placed the order, the race was on to make sure the house was ready when the windows finally arrived.  18 WEEKS LATER they finally arrived. when we finally opened the container door to check them out, 2 of the biggest units had broken free from their braces and had fallen over at somepoint during shipping.  while nothing was catastrophic, there were issues both functional and aesthetic.

fast forward 6 weeks.  zola has been super responsive and we’re confident that in the end everything will be as good as new.  the windows and doors are installed and are beautiful.  the house is dry, the first blower door test went well (.44ach at 50pa), and we are steadily moving toward insulation and sheetrock.

here’s a quick look at some of the process. first, prepping the rough openings:

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step 1 – use pink prosoco joint and seam filler at corners and joints of rough opening.

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step 2 – use red prosoco fast flash to coat rough opening and extend approx. 6″ out onto sheathing.

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to apply these prosoco products, simply lay down a bead from a caulking gun and spread with a cheap plastic spreader.  the result is a waterproof, airtight, and vapor permeable flashing without the usual complications of peel and stick flashings.  of course no through wall metal flashings on a passivhaus.

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next, windows arrive and are unloaded.

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not what you want to see when you open the door of the container.  i think they forgot to do the ACTUAL bracing at the factory.

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some of these units are HEAVY!  thank to Doug Marshak and his Awesome Framing Crew for doing the very heavy lifting.

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small tilt/turn unit for the kitchen.

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Doug and Jesus installing the small window in the 2 story living room.

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the big units waiting to be installed.

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after a few nervous hours, the biggest unit finally goes in.  thanks to Graeme Thomson for the smart hoisting method.

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the large fixed unit installed above the lift/slide door.

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front door with translucent glass and large window to the street.

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breezeway with tilt/turn terrace door and fixed sidelite.

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studio with tilt/turn door and fixed sidelite.

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check back soon for more as we try to catch up with construction: HRV rough-in, steel stair installation, flashing the windows, installing the exterior insulation, and rainscreen furring.

air sealing

November 11, 2012

air tight per passivhaus = .60 ach at 50pa.  if you don’t know the terms or numbers, just know that this is extremely air tight.  achieving this requires care and attention to detail, both in the design approach and in the execution.

our air barrier strategy is simple – use the exterior plywood roof and wall sheathing as the continuous air barrier.  all seams, corners, and joints in the plywood are taped with SIGA wigluv tape.

the sill plate is taped to the concrete foundation (our 2×8 sill is cantilevered beyond the foundation).  the concrete is first primed with SIGA dockskin primer to ensure adhesion.  carefully apply tape.  the result is an air tight joint.  simple.

the plywood air barrier runs up the wall and over the roof.  the joint is taped and then the parapet is framed on top.  after seeing some tears in the tape we got nervous and taped the parapet too.

all roof and wall penetrations are sealed.  we used SIGA wigluv for these too.

the tapes are super sticky, very flexible and easy to use.  the paper backing is recyclable, which is good because there is a lot.

it’s not inexpensive though, and we used far more than we originally thought.  air sealing takes time too.  it’s worth it though.

SIGA tapes are available through small planet workshop.

another great exterior air sealing product is prosoco joint and seam filler (used at rough openings in combination with prosoco fast flash).  more on that in the next post.